It is commonly accepted that there is no free heme within the cell under homeostatic conditions (i.e., heme is either bound tightly by hemoproteins, heme chaperones, or heme scavengers)85, but it is possible that heme may be spuriously released under dyshomeostasis during oxidative stress or infection within the cell, a situation that could lead to the observed decrease in ATE1 activity. Here, ATE1 is linked to infection.